I have to lock my carbon fiber bike to a fence outside and I am not very happy about this... The building I am in doesn't allow bikes inside, despite being filled with and environmental non-profits... I chose to use the office that overlooks the bike area. Most people don't want this office, but for me it was perfect. I use a u-lock and a cable through the tires. My seatpost is specially designed to only fit the frame I have, so if someone stole it, they wouldn't be able to do much with it. I also have renters insurance, mostly for my bike, just to feel less anxious about loosing my bike. Worth the $15 bucks a month for me. I don't leave any lights or anything on it during the day. I drive if there is heavy rain or storms (very rare where I am), but with light rain in the forecast, I put a bag over the saddle. You can also buy waterproof bike covers - check Amazon, bike nashbar, etc. I have been considering one of these, but then there is the issue of what to do with a wet bike cover at the end of the day...